Prevalence and anatomic characteristics of infarct-like lesions on MR images of middle-aged adults: The atherosclerosis risk in communities study

BACKGROUND AND PURPOSE: MR imaging has revealed putative evidence of subcli nical cerebrovascular disease (CVD) as reflected by white matter signal cha nges and infarct-like lesions (ILLs), Nonetheless, the prevalence of this c ondition in the general population has been defined only to a limited exten t, We herein report the prevalence and anatomic characteristics of ILLs see n on cranial MR images obtained as part of a population-based study of card iovascular disease in middle-aged adults, These results are contrasted to t hose of previous similar studies, particularly those of an elderly populati on in the Cardiovascular Health Study (CHS), METHODS: This Atherosclerosis Risk in Communities (ARIC) cohort consists of a probability sample of community-living persons who were 55 to 72 years o ld at the time of MR examination, MR imaging of 1890 participants was perfo rmed at two ARIC field centers, based on a common protocol. MR studies were evaluated by trained readers at the MR Reading Center using original digit al data displayed on a high-resolution workstation, The measures of lesion size, anatomic location, and signal intensity were collected, The definitio n for an ILL was a non-mass, hyperintense region with an arterial vascular distribution on spin-density and T2-weighted images, RESULTS: Two hundred ninety participants had ILLs, for an overall prevalenc e of 15.3%, Eighty-two percent of participants with ILLs had lesions that w ere 3 mm or larger in maximal dimension, although 87% of these lesions were 20 mm or smaller in maximal dimension, The prevalence of ILLs increased wi th age, from 7.9% in the 55- to 59-year-old age group to 22.9% in the 65- t o 72-year-old age group (P < .001). Lesion prevalence was greater in black (20.7%) than in white persons (10.2% [P < .0001]), but did not differ signi ficantly between male and female participants, The basal ganglia and thalam ic region was the most commonly affected anatomic site, accounting for 78.9 % of the lesions, CONCLUSION: Considering that the prevalence of self-reported stroke or tran sient ischemic attack in ARIC participants is 1.5%, these results suggest t hat there is significantly more subclinical than clinical CVD in the genera l population, Furthermore, the prevalence of this subclinical disease incre ases with age, and is greater in black persons, ILLs are dominated by "lacu nae" in the basal ganglia and thalamus, These results are, in general, simi lar to those of a comparable study of elderly participants in the CHS, exce pt for a 60% lower prevalence of ILLs in this younger population.